Amount of torque for jointer carbide inserts.

[C Scott McDonald]

Well, the time has come to rotate the inserts for the first time. I was going to play it safe and get an inch pound torque wrench so I know they wont come loose. I know its probably over kill but I am not getting any younger and cant runaway as fast if things go sideways.

So what would be the correct torque setting? I checked the powermatic 54hh manual.and it just says to use torx screw driver? I imagine all these inserts are made in the same place so the setting would be the same.

Thanks
Scott McDonald

[John Ziebron]

Scott, my Grizzly jointer manual says to lubricate the screw threads with light machine oil and torque to 48-50 inch/pounds. I agree, I would think they should all the same torque no matter the manufacturer.

[Peter Christensen]

It isn't the insert that dictates the torque. It is the screw and the metal it is screwed into. Each maker will have different torques for their tools. Call the maker and get the correct value. In the metal machining industry many of the insert tools come with preset torque screwdrivers or have them as optional accessories.

I looked at Powermatic's website and it shows Byrd Shelix inserts in the accessories area for your jointer. On the Byrd site I found under Shelix Tip Installation they recommend 45 inch pounds of torque.

http://www.byrdtool.com/tech-corner

[John K Jordan]

I was going to play it safe and get an inch pound torque wrench so I know they wont come loose.

I think you are wise to use a torque wrench, even if you have no clear torque specs. This will provide consistency for each insert.

I keep torque wrenches in various torque ranges and use them a lot for things like farm equipment, hydraulic pumps, vehicles, etc.

Most service manuals for equipment give torque specs for key fasteners and/or a table with specs by bolt size, usually given as a range rather than an exact number. You can also look up generic torque specs by bolt size and type which should be close enough for everything but critical applications. I have learned to not rely on what someone tells me but look it up to see if the number makes sense. For example, when rebuilding a hydraulic pump the service manager where I bought the seals gave me a torque value - when I started the assembly I realized the numbers he gave me were WAY over what "felt" right for that size of bolt, verified by a quick google search. (And it wasn't a simple matter of inch vs foot pounds confusion.)

I believe an important step is often missed: cleaning the mating surfaces and cleaning and lubricating the threads for smooth tightening and accurate/consistent torque. (When reusing bolts I clean the threads with spray brake cleaner and a wire brush if needed.) Contrary to sometimes popular misconceptions, lubricating bolt/nut threads will not affect the holding power or allow a fastener to loosen. This may not be as important with the small bolts used with woodworking equipment kept indoors but for carbide inserts even a bit of sawdust in the wrong place can't be ideal!

JKJ

[Nick Decker]

FWIW, the carbide inserts on my Cutech 13" planer call for 48-50 inch lbs.

[Grant Wilkinson]

+1 on JKJ's comment. I maintain a jointer and planer at a commercial shop. When it's time to rotate the cutters, I remove all of them, clean the heads thoroughly, put anti-seize on the bolts, then put everything back together. It adds alot to the time it would take to simply loosen the bolts, rotate the cutters and re-tighten the bolts, but it make a world of difference in the finish we get on the boards.

[glenn bradley]

+1 on JKJ's comment. I maintain a jointer and planer at a commercial shop. When it's time to rotate the cutters, I remove all of them, clean the heads thoroughly, put anti-seize on the bolts, then put everything back together. It adds alot to the time it would take to simply loosen the bolts, rotate the cutters and re-tighten the bolts, but it make a world of difference in the finish we get on the boards.

Amen to that. Take the time to do it right. It pays in the finish you receive as a result.

Your manual should have the torque specs for your particular head. My G0490X is older and uses the originally offered cutterhead (I think their are 3 now). From the manual:

Lubricate the Torx screw threads with a very
small amount of light machine oil, wipe the
excess off, and torque the screw to 50–55
inch/pounds.

Note: If too much oil is applied to the threads,
the excess will attempt to squeeze out of the
threaded hole as you install the insert and
force it to raise slightly, which will make it out
of height alignment.

[Bill Space]

A while back, in a related thread, Ken Fitzgerald posted an excellent review of the correct procedure for using a torque wrench.

Unfortunately I can't find that thread. :mad:

Bottom line is there is more to properly torquing an insert screw than simply tightening it fully the first time. One reaches the final torque in steps. Ken's procedure explained the process in detail.

Anyone remember the the thread I am referring to? If so, please tell us!

Bill

[John K Jordan]

A while back, in a related thread, Ken Fitzgerald posted an excellent review of the correct procedure for using a torque wrench.
Unfortunately I can't find that thread. :mad:
Bottom line is there is more to properly torquing an insert screw than simply tightening it fully the first time. One reaches the final torque in steps. Ken's procedure explained the process in detail.
Anyone remember the the thread I am referring to? If so, please tell us!
Bill


Bill, is this the one?
http://www.sawmillcreek.org/showthread.php?225454-Torque-wrench-left-improperly-torqued&p=2351922#post2351922

The text of Ken's message:

Before I retired, I had a set of torque wrenches that had to be calibrated annually. We also had to take a class in using them. We were taught to reset/release the tension on them each time after you are done using them.

We were also taught to not "reef" on them until you see the correct tension or hear the "click" because overshoot is quite common and the amount of overshoot can be pretty dramatic. Rather, we set the wrench to 1/2 the desired torque, ease on it until that value is reached; complete that step on all related fasteners, then set to the final value and gradually apply pressure to "ease" to the final value on all related fasteners. Finish with all respective fasteners (bolt or nut). Do not go back and check as it usually results in causing over tightening.

A lot of what I just stated was demonstrated during the class with students doing the torquing and then instructors measuring and demonstrating the overshoot or improper values.

While actual torque values are important, IMO, in most cases what is important is equal torque on related bolts/nuts such as lug nuts or head bolts etc.

Torque becomes very important in some cases like the newer CT scanners. Imagine when you are laying on the patient pallet being scanned, there is an x-ray tube that can weigh as much as 350+lbs. and in some cases it is spinning around your body at speeds of 3 revolutions per second..... If that tube comes off at that speed, BAD THINGS CAN HAPPEN. There were torque specifications for every bolt, screw and nut holding every component on that rotating frame.

Torque can be important.

Last edited by Ken Fitzgerald; 12-26-2014 at 8:17 PM.

[Bill Space]

I believe that is it, John.

I remember at at the time that I realized that I did not realize that one should torque things in steps, rather than just doing it once.

Thanks for finding the thread!

Bill

[Jesse Busenitz]

So I just hit a nail in some reclaimed lumber that snuck past my metal detector, and I had to turn a couple. I used my impactor which was wayyyyy to much torque. Which reminds me I need to order some spare cutters.

[Peter Christensen]

So I just hit a nail in some reclaimed lumber that snuck past my metal detector, and I had to turn a couple. I used my impactor which was wayyyyy to much torque. Which reminds me I need to order some spare cutters.

You should also get some new screws to replace the ones you over torqued. ;)